In London alone, the movement says it has 1,000 people giving away literature - and they get through about 6,000 brochures, 20,000 books, and 100,000 magazines every month.

The tactic was pioneered in New York three years ago and is set to expand further. At weekly congregation meetings, volunteers are encouraged to let passers-by approach rather than trying to stop them. The tactics seem the polar opposite of the doorstep approach - most of the day the volunteers stand there smiling but saying little.

At Oxford Circus, in the centre of London and the fourth busiest underground/metro station in the UK, the Jehovah's Witnesses are passed by hundreds of thousands of people every week.

Deep Singh, a coordinator for this latest street drive, who converted from Sikhism 23 years ago, stands with his arms outstretched, holding books with the title, What does the Bible really teach?, in capital letters. His wife, Ruth, meanwhile, hovers by a stand, stocked with copies of Awake!, the Jehovah's Witnesses' flagship magazine. The couple are joined by another volunteer. And the station's other entrances and exits are manned by other groups.

Even standing by the volunteers for an hour, it seems that few passers-by stop to talk.

Image copyrightGetty ImagesImage caption
Recruitment drive in London in 1966

The movement doesn't have figures for how many converts this part of its mission has produced. And it's emphasised that it's an addition rather than a departure from the door-to-door evangelism, but adherents are optimistic that the new tactic is making an impact.

The UK Jehovah's Witnesses say that the May issue of Awake!, with its cover line Stress - Keys to Managing It, was the most popular of the current drive.

"People were queuing up for a copy in the City [of London]," says Deep. "One woman asked if it was possible to take copies for her colleagues because she said her whole office was stressed."

The Singhs are both cutting back on their paid work away from the movement in order to be, as Deep states on his WhatsApp mobile messaging profile, "On the Lord's Work!!" from 7am-7pm. "I feel for people. Life is a mess, and we help to improve people morally, spiritually and emotionally," says Deep.

"This ministry is definitely better for secular people who like to be in control," he adds. "They can ignore us, ask questions or just pick up a book to get the answers they're looking for." Ruth, who grew up with a Jehovah's Witness mother and atheist father, agrees. "It makes sense," she says. "People are so busy and this ministry conveniently fits in with their hectic schedules."

Jehovah's Witnesses at a glance

Image copyrightWatch Tower Bible & Tract Society

Founded in the US towards the end of the 19th Century, under the leadership of Charles Taze Russell. Headquarters of the movement in New York

Although Christian-based, the group believes that the traditional Christian Churches have deviated from the true teachings of the Bible, and do not work in full harmony with God

The traditional Christian Church does not regard the movement as a mainstream Christian denomination because it rejects the Christian doctrine of the Trinity

Jehovah's witnesses believe that humanity is now in the 'last days' and that the final battle between good and evil will happen soon

But Scott Terry, a former Jehovah's Witness for 14 years and author of Cowboys, Armageddon, and The Truth: How a Gay Child Was Saved from Religion, believes that a widespread apathy towards door-to-door ministry is behind this latest approach.

"Many of the Jehovah's Witnesses I know detest door-to-door work," says Terry. "Yet they are required to turn in their time cards each month to prove that they have spent the required hours preaching. I know Jehovah's Witnesses who go to great lengths to stretch those hours by including time spent in the car, travelling to the designated neighbourhoods.

"Setting up at a train station is the easy way out. It is less confrontational than knocking on people's doors, and it is an easier way to acquire the hours needed to remain in good standing in the congregation."

The movement regards the street drive as just another way of proselytising, says Mark O'Malley, a spokesperson at the Office of Public Information for Jehovah's Witnesses. And there have been many different tactics. "'Photo-Drama of Creation' was released in 1914. It combined moving pictures, sound recordings, and coloured glass slides to re-enact Biblical scenes. In the 1920s, we started to use the radio to spread the message from the Bible.

"Today, jw.org, which can be navigated in more than 300 languages, receives about one million individual hits each day."

Famous witnesses

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Prince (pictured) - the singer/songwriter was brought up as a Seventh Day Adventist, but became a Jehovah's Witness in 2001, shortly after the death of his parents

Venus and Serena Williams were brought up as Jehovah's Witnesses - "God and tennis are my priorities in life," said Serena in 2012

Hank Marvin is a devout Jehovah's Witness, but told one newspaper that he no longer took part in door-to-door missionary work: "Whenever I knocked on anyone's door, they thought it was Candid Camera playing a practical joke on them.

And in some senses, the current street drive is a return to previous tactics.

"There are many recorded instances of preaching in public places in the 1930s and 1940s that I am aware of but, in my opinion, the Witnesses began favouring door-to-door preaching in the 1960s," adds Terry.

"The Jehovah's Witnesses is a proselytising religion and its members believe that aggressive ministry is essential for the inauguration of Armageddon and the subsequent New Kingdom," says Dr Andrew Holden, author of Jehovah's Witnesses: Portrait of a Contemporary Religious Movement. "At one time, it was common for the Jehovah's Witnesses to minister and to distribute their literature in busy city centres until their evangelistic activities were curtailed, both by law and by local council policy."

The Jehovah's Witnesses, with a global membership of almost eight million people, believes that we are now living in the "end times", says Holden, but that this will only be fulfilled when the "true" word of God has been ministered to the ends of the earth.

"The street drive is, in the Jehovah's Witnesses' terms, the final push for converts before the millenarian age begins," he adds.